A wireless device (e.g., a cellular phone or a smartphone) in a wireless communication system may transmit and receive data for two-way communication. The wireless device may include a transmitter for data transmission and a receiver for data reception. For data transmission, the transmitter may modulate a radio frequency (RF) carrier signal with data to obtain a modulated RF signal, amplify the modulated RF signal to obtain an amplified RF signal having the proper output power level, and transmit the amplified RF signal via an antenna to a base station. For data reception, the receiver may obtain a received RF signal via the antenna and may amplify and process the received RF signal to recover data sent by the base station.
Many modern electronic systems (e.g., wireless device) rely on one or more batteries for power. The batteries are typically recharged, for example, by connecting the electronic system to a power source (e.g., an alternating current (AC) power outlet) via a power adapter and cable.
A regulator or voltage regulator may provide a power supply rail from a battery. The voltage regulator increasingly has to service multiple subsystems (e.g., loads) in electronic devices. These subsystems may have different power supply voltage specifications and load current specifications. The power delivery capability of the voltage regulator, however, is limited by the power available from the battery. Under certain conditions, the voltage regulator may not be able to provide sufficient power to meet all the demands of all the device subsystems. When load currents of multiple ones of the device subsystems increase, the power supply voltage at the output of the voltage regulator (Vout) may droop, causing one or more of the device subsystems to fail.